Reproduction, breeding, repatriation, and monitoring of tortoises
For more information contact:
X, Process of Conservation and Restoration of Island Ecosystems
+593 (0)5 252 6189, email@example.com
Tortoises raised in captivity are repatriated when they become old enough to survive alone.
Giant tortoises are the most representative species of the Galapagos. The arrival of humans to the islands, however, brought about dramatic consequences for them, reducing their number from about 250,000 to the 20,000 individuals that exist today. The Directorate of the Galapagos National Park works for the conservation and recovery of the 11 remaining species.
GIANT TORTOISE DISTRIBUTION
» Distribution Map
Both the number and the geographical distribution of tortoises have been reduced considerably, with the arrival of humans on the Islands in the sixteenth century.
After the creation of the Galapagos National Park and with the establishment of the Charles Darwin Research Foundation on Santa Cruz Island between 1959 and 1960, research was begun to determine the status of some reptile populations, particularly tortoises and land iguanas.
From 1960 to 1964 some of the fears were confirmed.
Of the 14 species of tortoises very well identified by the scientist Van Denburgh in 1914, some were already extinct for various reasons such as:
- capture by humans
- acts of nature (volcanic eruptions)
- predation by introduced species like dogs, rats, and pigs
- human predation
POPULATIONS AND THREATS
» View reports
Although the results so far are encouraging, much work remains to be done to protect these species, some of which are seriously threatened by introduced species.
In 1965, on Santa Cruz, the Charles Darwin Foundation began a breeding and repatriation program for giant tortoises (Geochelone elephantopus) of Pinzón Island. Over the next years, the program was expanded to include other threatened tortoise populations such as the ones on Española, Santiago, San Cristóbal, Isabela, and Pinta Islands.
In 1968, the work of the Directorate of the Galapagos National Park began with the protection management programs, breeding in captivity, and the repopulation of the habitats of endangered tortoises.
Tortoise reproduction and breeding
Twice a year, the Directorate of the Galapagos National Park conducts expeditions to monitor giant tortoise populations, where the eggs of the most endangered species are collected.
On the first trip, during the nesting season, the location of the nests is determined using GPS. About four months later, when the eggs are about to hatch, a second collection trip is conducted. Sometimes precocious tortoises are collected, newly hatched from the tagged nest.
Eggs from nests that are made by adult tortoises in captivity are also collected.
Hatchlings remain together and isolated from the rest during their stay at the Breeding Centers.
Much of the reproduction and breeding work takes place at the Fausto Llerena Breeding Center, located in the facilities of the Directorate of the Galapagos National Park and the Charles Darwin Research Station on Santa Cruz Island.
Today, the Fausto Llerena Breeding Center hosts more than 1,000 tortoises from the islands of Santa Cruz, Santiago, Pinzón, and Española. Seventy five of these individuals are adults and are held at the Center for reproductive and ecotourism purposes.
HELP FOR NEW GENERATIONS
» Tortoise reproduction and breeding
Reproduction and breeding in captivity is contributing to the recovery of tortoise populations and the extinction of the Española tortoise (Geochelone hoodensis) has been prevented.
In 1989, the construction of the tortoise breeding center in Puerto Villamil, Isabela Island began, and started to operate in 1994. There, populations of tortoises of the Sierra Negra and Cerro Azul Volcanoes are held in captivity, because the threat posed by human presence and introduced species is latent.
Currently it is home to about 900 turtles, all from Isabela Island, 65 of which are adults.
In 2004 the Jacinto Gordillo Breeding Center (named after the famous colonist) was inaugurated and located in "La Galapaguera" of Cerro Colorado, on San Cristóbal Island, to care for the smallest tortoises on that island. The breeding program on that island began in 2008 with the hatching of the first tortoise in captivity.
On Floreana Island, a pen has been built to protect and maintain 32 adult and young tortoises of uncertain origin. The pen is only for the care of the tortoises and for tourist observation, not for reproduction.
The Charles Darwin Foundation provides ongoing technical assistance to the Directorate of the Galapagos National Park for its breeding in captivity program.
The assistance of international scientists is also an important collaboration to ensure the future of these animals.
» Tortoise repatriation
When their shell curve reaches 20 centimeters, they are tagged for future identification and monitoring, and they are packed for transportation to their places of origin.
Upon reaching an acceptable size, the tortoises are repatriated to the original locations of their species.
Over the years, the breeding in captivity program has ensured the survival and has repatriated more than 2,500 tortoises to Santa Cruz, over 1,500 between the various species to Isabela, over 600 to Pinzón Island, and over 1,600 to Española Island.
The survival rate has improved thanks to the head start that the tortoises get at the breeding center.
This work must continue until the populations of Galapagos giant tortoises reach a balance in their rate of reproduction in the wild, and are safe from the introduced species that threaten them.
Although there is still much work to do, the results so far are encouraging. On Española, where the population was reduced to only 15 individuals, over 1,600 tortoises have been returned to the island to this day.
Repatriated tortoise tracking and population monitoring.
» Monitoring of tortoises
The status and health of different populations of giant tortoises is continuously monitored.
Tortoises that have been bred in captivity also fulfill a vital role in monitoring the populations from which they come.
Having been tagged prior to repatriation, they are identifiable by the Park Rangers and scientists who go on collection, monitoring, and repatriation expeditions.
Monitoring is crucial because the tortoises in their natural state are still suffering the consequences of the introduction of the following invasive species:
- Donkeys and cattle that trample and destroy their nests, disturbing the delicate balance of moisture in the earth needed for the successful incubation of eggs.
- Pigs and dogs that destroy the nests and eat the eggs.
- Black rats that hunt the hatchlings when they emerge from their nest.
- Introduced fire ants that are capable of killing the hatchlings in their nests and destroying the eggs.
- Feral goats that compete with tortoises for food and destroy the land.
While programs for the control and eradication of introduced species continue, giant tortoise populations will be monitored to assess their numbers and health status.
Although the number of tortoises in the wild has increased from about 3,000 in 1974 to 20,000 today, there is still much work to be done. The Directorate of the Galapagos National Park carries on with continuous monitoring, supported by the Charles Darwin Foundation and international scientists and research institutions, in order to protect the original inhabitants of the islands.
This program has counted on the support of:
The Charles Darwin Foundation for the Galapagos Islands (CDF) is an international nonprofit research organization dedicated to providing scientific research, technical assistance and information in order to ensure the success of conservation in Galapagos.